Piston for internal-combustion engines



J. BOLAN.

PISTON FOR INTERNAL COMBUSTION ENGINES.

APPLICATION FILED 05c. 30, 1920.

1,402,893 Patented 3, 1922.

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James YIBOLAN, orlnosron, mAssAoH'osEr-rs."

PISTON-FOR INTERNAL-COMBUSTTON' ENGINES.

Specification of Letters Patent. Pat t d J 3 192% Application filed December 30, 1920. Serial-No. 434,024.

. chusetts, have invented new and useful Improvements in Pistons for Internal-Combustion Engines, of which the-following is a specification.

This invention relates to an improved pie ton for internal combustion engines.

In an internal combustion engine carbon is liable to form in the compression chamber and gather on the compression rings and the underside of the piston head and it is very desirable that the engine should be free of carbon in orderto secure the greatest elliciency. In internal combustion engines having a piston in'one piece connected to the connecting rod, in order to perfectly remove the carbon'it is necessary to drain the oil from the oil pan, take off the oil pan, discon nect the connectin rod from the crank and push the connecting rod and piston up through the top of the cylinder. This is a very diflicult operation and involves a large amount of labor and loss of time.

The object of this invention is to rovide a piston which will overcome these di culties and this result is attained by making the piston in two parts, a body portion and a head portion, so connected together that the head portion with the compression rings can be removed from the cylinder and replaced therein in a few minutes.

It is further the object of this invention to provide a piston in which the upper portion moves up and down and does not have any side thrustv from the connecting rod thereon.

Another object of the invention is to so construct the upper part, or head portion of the piston, as to prevent over-heating of the oil in the crank case and bearings.

To these ends the invention consists ina piston for internal combustion engines hav-- Fig. 2 is a sectional elevation taken on the line 22, Figure 1, showing a portion of a cyllnder in connection with the. piston. Fig. 3 1s a sectional elevation similar to Fig. 2 but with the head of the piston dis-.

connected from the body portion thereof.

Fig. 4 1s-.a side elevation partly in section of the bridge, the section being taken on the lme 2-2, igure 1.

'Like numerals refer to like parts throughout the several views of the drawings.

In the drawings, 5 is the piston consisting of a body portion 6 and a head portion 7. The body portion is preferably provided with annular grooves 8 and compression rings 9. The body portion forms a loose fit ma cylinder 10 in the usual manner, while the rings 9 form a close fit therein. The body portion is provided with a pair of oppositely disposed inwardly extending hubs 11 and located in each of these hubs is a bushing 12. The inner ends of the bushings'12 project inwardly beyond the inner ends of the hubs '11 and upon the inner ends of the bushings a bridge 13 is piv otally mounted, said bridge has a hollow boss 14 thereon extending upwardly and having a screw thread 15 on the outside and a screw thread 16 on the inside. 17 is a piston pin to which the usual connecting rod 18 is connected.

The head portion 7 of the piston is provided with annular grooves 19 on its periphery and with compression rings 20 located in said rooves. The piston head 7 forms a loose tin the cylinder 10 and the rings form a tight fit therein in the usual manner. The

piston head 7 preferably consists of a central web 30 with an annular flange 31 thereon in the periphery of which are provided theannular grooves 19, said web and flan e being preferably formed of cast iron. n

the cylindrical space on opposite sides of the web 30 two discs 32 and'33 are provided and these are preferably formed of aluminum. These circular discs are each provided withan annular space'3 l and these spaces may be either left empty for air space for the sake of lightness or they may be filled with packing as may be desired. Ascrew 23 is fastened to the head 7 by nuts 35 and 36 and projects downwardly and beyond said head to engage a nut 24 which is screw threaded upon the outside to receive a spring 25, the lower end" of which extends into and is in screw-threaded engagement with the screw thread 16 on the OS 14 on the bridge 13 to which it is fastened. An

. -other spring 26 is interposed between the head portion 7 and the bridge 13, the lower end of the spring resting upon a shoulder 27 on said bridge.

- The head portion 7 is provided with a slot 28 through which the end of a screw driver may be inserted to engage the screw 23' and by means of which the head portion can be 10 rotated in the cylinder 10 to cause the screw 23' to engage the nut 2 L and lock the parts together as illustrated in Fig. 2. The spring 25 is wound in such a manner that when the head 7 is locked by the screw 23 to the body ortion 6, as illustrated in Fig. 2, by screwing'the screw'23 into'the nut 24, said spring will be\expanded or under tension. The spring 26, on the contrary, when the head 7 is locked to the body portion 6, as illus- 2 trated inFig. 2, is under compression, so that when the piston head 7 is rotated to detach the screw 23 from the nut 24 the head portion 7 will be forced partly out of. the cylinder by the spring 26, as illustrated in 25 Fig. 3 and the spring 25 being released by the. screw 23 will assume the position illustrated in Fig. 3 where the coils of the spring are drawn together and contact with each other.

The main body portion 6 is provided on its upper edge with two projections 29 which are diametrically opposed to each other, each preferably V-shaped, see Figs. 1 and 2. The

lower edge of the head portion 7 rests upon these V-shaped projections when the parts are assembled as illustrated in Fig. 2 and thus the force of the explosion will be transmitted 'from the head 7 through the V- shaped projections to the body portion 6 of 4 the piston.

' v The general operation of the piston hereinbefore specifically described is as follows :Assuming the parts to be in the relative positions illustrated in Fig. 3, the piston 4 head is pushed downwardly into the cylinderuntil the lower end of the screw 23 en gages the nut 24:. The piston head is then rotated by means of a screw driver, or other desirable tool, until the screw has entered 0 the nut and the parts of thepiston assume the relative positions illustrated in Fi re 1 with the screw inserted in the nut an with the spring 26 compressed. This operation causes the nut 24 to be pulled upwardly, placing the spring 25 under tension. To remove the piston head portion 7 from the cylinder, the reverse of the operation just described is performed.

In operation, the body portion 6 of the 50 piston is moved upwardly and downwardly with the connecting rod 18 and wrist pin 17 in the usual manner. It will be evident that all lateral thrust upon the piston, as a .whole, will be taken by the body portion 6 and that a s9 lateral thrust w be imparted to the head portion 7. When the piston head and.

body are driven downwardly by the explosion of the compressed gas in the cylinder 10, the head portion 6 is forced downwardly and through the V-shaped projections 29 forces the body portion of the piston downwardly and thus through the piston pin 17 a downward motion is imparted to the connecting rod 18 and the crank shaft is rotated in the usual manner. I During the intake stroke, however, the head portion 7 is drawn upwardly and carries the body portion with it by means of the screw 23, nut 24:, spring 25, bridge 13 and piston pin 17. Thus, during the upward movement of the piston, as a whole, the two parts are held together against the suction of the intake by thespring 25...

In the operation of the piston, any slight lateral variation or movement of the body portion 6, due to the thrust thereon of the connecting rod 18, will not be transmitted to the piston head 7 for the reason that said piston head is connected to the connecti rod 18 by the sprin 25 and said piston hea is pivotally and s idably' mounted on the body portion 6 through the V-shaped projections 29, which constitute fulcrums by reason of which the body portion 6 can rock relatively to the piston head 7.

' It will be evident that from the two-part construction of the piston hereinbefore described and the particular manner in which the piston head is connected to the piston body by a spring, and by the V-shaped projections on the body bearing against the underside of the head that any wear on the walls of the cylinder, due to lateral thrust, will take place only throughout the extent of that portion of the cylinder with which the body portion of the piston comes in contact, but that portion of the cylinder w1th which the head comes in contact will not be worn by the head as there is no lateral thrust on it. Therefore, the compression will at all times be practically perfect.

I claim:

1. A piston for internal combustlon engines having, in combination, a body portion and a head portion, pivotal means whereby said head portion is pivotally mounted on .said body portion and means other than said pivotal means connecting said head portion to said body portion.

2. A piston for internal combustion engines having, in'combination, a body portion .and a head portion, pivotal means whereby. said head portion is pivotally mounted on said body portion and means other than said pivotal means detachably connecting said head ortion to said body portion.

3. 2 piston for internal combustion engines having, in combination, a body portion and a head portion, said head portion being pivotally mounted on said body portion and means yieldingly connecting said head portion to said body portion.

4. A piston for internal combustion engines having, in combination, a body portion and a head portion, a pair of diametrically opposed projections constituting fulcrums, located on one end of one of said parts and adapted to bear against the adjacent end of the other of said parts and means connecting said head portion to said body portion.

5. A piston for internal combustion engines having, in combination, a body portion and a head portion, pivots extending transversely of said body portion, means connectingsaid head portion to said body portion, a bridge mounted on said pivots and extending upwardly therefrom within said body portion and a spring interposed between said head and bridges and adapted to move said head portion away from said body portion.

6. A piston for internal combustion engines having, in combination, a body portion and a head portion, pivots extending transversely of said body portion, a bridge vmounted on said pivots and extending upwardly therefrom within said body portion, a spring connected at one end thereof to said bridge and projecting toward said head portion, a nut fast to the other end of said spring and a screw on said head portion adapted to engage said nut, whereby upon the rotation of said head portion it will be drawn toward said body portion.

7. A piston for internalcombustion engines having, in combination, a body portion and a head portion, said head portion being pivotally mounted on said body portion, pivots extending transversely of said body portion, a bridge mounted on said pivots and extending upwardly therefrom within said .body portion and a spring interposed bepiston for internal combustion engines having, in combination, a body portion and a head portion, said head portion being pivotally mounted on said body portion, pivots extending transversely of said body portion, a bridge mounted on said pivots and extending upwardly therefrom within said body portion, a spring fast at one end thereof to said bridge and projecting toward said head portion, a nut fast to the other end of said spring and a screw on said head portion adapted to engage said nut, whereby upon the rotation of said head portion it will be drawn toward said body portion.

9. A piston for internal combustion en'- gines having, in combination, a body portion and a head portion, said head portion being pivotally and slidably mounted on said body portion, a pivot extending transversely of said body portion, means connecting said head portion to said body portion, abridge mounted on said pivot and extending upwardly therefrom within said body portion, a spring interposed between said head and bridgeand adapted to move said head portion away from said body portion, a piston pin extending transversely across said body portion, and a connecting rod connected to said piston pin. a

In testimony whereof. I have hereunto set my hand in presence of two subscribing witnesses.

JAMES BOLAN. Witnesses:

CHARLES S. GOODING, FRANKLIN E. Low. 

